Low‐Power and Field‐Free Perpendicular Magnetic Memory Driven by Topological Insulators

Abstract Giant spin–orbit torque (SOT) from topological insulators (TIs) has great potential for low‐power SOT‐driven magnetic random‐access memory (SOT‐MRAM). In this work, a functional 3‐terminal SOT‐MRAM device is demonstrated by integrating the TI [(BiSb) 2 Te 3 ] with perpendicular magnetic tunnel junctions (pMTJs), where the tunneling magnetoresistance is employed for the effective reading method. An ultralow switching current density of 1.5 × 10 5 A cm −2 is achieved in the TI‐pMTJ device at room temperature, which is 1–2 orders of magnitude lower than that in conventional heavy–metals‐based systems, due to the high SOT efficiency θ SH = 1.16 of (BiSb) 2 Te 3 . Furthermore, all‐electrical field‐free writing is realized by the synergistic effect of a small spin‐transfer torque current during the SOT. The thermal stability factor (Δ = 66) shows the high retention time (>10 years) of the TI‐pMTJ device. This work sheds light to the future low‐power, high‐density, and high‐endurance/retention magnetic memory technology based on quantum materials.